Asset tracking is of paramount importance in a number of industries such as the trucking industry and the equipment leasing and rental industries. Knowing the location of equipment, trucks and shipped goods enables predictive planning of actual events and better management of drivers and assets. For instance, good communication between a vehicle (and/or its operator) and its dispatcher advantageously permits scheduling controls. Good communications systems also address concerns regarding equipment, vehicle and/or freight theft. Wireless communication systems are well known for transmitting information between fixed stations and one or more geographically dispersed mobile receivers carried in trucks or on a piece of equipment. For example, the Global Positioning System (GPS), a system of low earth orbiting satellites, has been used to determine a piece of equipment's or a vehicle's position. Further, satellite communication systems have also been used in the trucking industry for many years to provide messaging information between fleet-owned dispatch centers and their respective tractor-trailer vehicles. Such systems offer significant benefits to fleet owners because they allow almost instantaneous communications and real-time position information. An example of such a satellite communication system is disclosed in U.S. Pat. No. 4,979,170 entitled “Alternating Sequential Half Duplex Communication System and Method”; U.S. Pat. No. 4,928,274 entitled “Multiplexed Address Control in a TDM Communication System”; U.S. Pat. No. 5,017,926 entitled “Dual Satellite Navigation System”; and U.S. Pat. No. 6,124,810 entitled “Method and Apparatus for Automatic Event Detection in a Wireless Communication System,” all of which have been assigned to the assignee of the present invention and all being incorporated herein by reference thereto.
In the satellite communication system described in the above-mentioned patents, fleet-owned dispatch centers communicate using land-based systems such as telephone or fiber-optic networks with a hub, otherwise known as a network management facility (NMF). The NMF acts as a central communication station through which all communications between vehicles and a dispatch center pass. The NMF includes a number of Network Management Centers (NMCs), each NMC being responsible for providing a communication path for the NMF to geographically dispersed vehicles and/or equipment in the communication system using a geo-stationary satellite. A geostationary satellite includes one or more transponders. Transponders relay up and down link signals, (providing amplification and frequency translation) between geographically-dispersed earth stations which may be fixed or in-motion. Each NMC is assigned with different up and down link frequencies in order to avoid interference involving other Mobile Communication Terminals (MCTs) that are operating on the same satellite but with a different NMC. In the satellite communication system of the above referenced patents, each NMC system is capable of handling the communication needs of approximately 30,000 vehicles. Each MCT in the communication system comprises; a transceiver, modulator/demodulator, a CPU and GPS receiver which allows for text message exchange between the driver and dispatcher and position determination of the vehicle.
Access to and security of machinery, vehicles and freight are of the utmost importance and such concerns have come under greater scrutiny as of late. Of particular concern is the theft of vehicles or equipment or the unauthorized use of vehicles or equipment, especially those vehicles carrying hazardous freight.
There is therefore a need to provide strict vehicle or equipment access control. A need also exists to employ wireless communication systems in a manner which enables access and/or verification or change of access to vehicles or equipment. Until now, no such system has offered such access control with the efficacy of the system to be described herein.
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